docs: def writexml(self, filename_or_file=None, indent="  ", newl=os.linesep, 
                   encoding="UTF-8"):
          """ Write the manifest as XML to a file or file object """
          if not filename_or_file:
              filename_or_file = self.filename
          if isinstance(filename_or_file, (str, unicode)):
              filename_or_file = open(filename_or_file, "wb")
          xmlstr = self.toxml(indent, newl, encoding)
          filename_or_file.write(xmlstr)
          filename_or_file.close()